1. Field of the Invention
The present invention relates generally to a snowmobile and, more particularly, to an improved component arrangement of a snowmobile.
2. Description of the Related Art
A conventional snowmobile includes an elongated body having a straddle-type seat extending along a rearward portion thereof to support an operator and one or more passengers of the snowmobile. A front end of the body is supported above the ground by one or more ski members and a rear end of the body is supported by a belt-type drive assembly. An engine is supported by the snowmobile body and is drivingly connected to the drive assembly to propel the snowmobile along the ground. In addition, suspension assemblies can be interposed between the body and the ski members and/or the drive assembly.
Increasingly, snowmobiles have utilized 4-cycle internal combustion engines in an effort to reduce emissions. The 4-cycle engine includes a crankcase rotatably supporting a crankshaft, an axis of which typically extends laterally, i.e., across the width of the vehicle. A cylinder assembly extends generally vertically from the crankshaft and defines one or more cylinder bores, each of which support a piston for reciprocation therein. Valve assemblies typically are positioned above the cylinder bores and are configured to selectively permit communication with combustion chambers defined in part by the cylinder bores and pistons.
In addition, the crankcase typically also supports a balancer shaft, which is coupled for rotation with the crankshaft and is adapted to offset an imbalance caused primarily by the movement of the one or more pistons. The inclusion of the valve assemblies and a balancer shaft results in the engine having a relatively large vertical dimension in comparison with a similar 2-cycle engine. As a result, the overall center of gravity tends to be higher when a 4-cycle engine is employed, in comparison to a snowmobile incorporating a 2-cycle engine. As is known by one of ordinary skill in the art, it is generally desirable to have a relatively low center of gravity in order to improve handling characteristics of the snowmobile.
Furthermore, the snowmobile typically is equipped with an intake system to deliver air and fuel to the engine and an exhaust system to evacuate exhaust gases from the engine. The intake system typically includes an air box defining a plenum chamber, which acts as an intake silencer. The air box also may be utilized to house an air cleaner element to filter air entering the engine through the intake system. In addition, a lubrication system to deliver lubricant to various moving parts of the engine and a cooling system to deliver a cooling fluid to the engine may also be provided. The snowmobile also includes a battery to provide electrical power to various components of the snowmobile, including the engine.
In order to maintain desirable dimensions of the snowmobile, the body provides a limited amount of space to accommodate all of the above-described components typical of a snowmobile employing a 4-cycle engine. Most prior snowmobile component arrangements have resulted in less than optimal handling characteristics. For example, prior component arrangements have resulted in the snowmobile having a center of gravity positioned too far forward and/or a center of gravity positioned too high relative to the body of the snowmobile, resulting in inadequate grip of the drive assembly with the ground surface and/or instability during turns or other lateral movements.